Magnetic expandable broadhead

Abstract

Magnetic expandable broadhead arrowheads and methods for magnetically holding the blades of broadhead arrowheads in the retracted position are disclosed. Embodiments include deployable cutting blades that are magnetically held in a retracted position during launch and flight and deploy outwardly upon impact with a target. Other embodiments include magnets where the force holding the cutting blades in the retracted position is localized adjacent either the deployable ends or the pivoting ends of the cutting blades. Still other embodiments include magnets adjacent to substantially the entire length of elongated cutting blades while the blades are in the retracted position. Alternate embodiments include elongated cutting blades that extend in a rearward direction when retracted and cutting blades that extend in a forward direction when retracted.

1. A broadhead arrowhead, comprising:
 a broadhead body adapted to attach to an arrow shaft, at least a portion of the broadhead body being magnetic wherein the magnetic portion of the broadhead body forms an elongated cylinder; and 
 cutting blades adapted to attach to an arrow shaft and having retracted positions with the cutting blades extending along the broadhead body and deployed positions with the cutting blades extending outward from the broadhead body; 
 wherein the magnetic portion of the broadhead body magnetically attracts and holds the blades in the retracted position during launch and flight; and 
 wherein the cutting blades are adapted to overcome the magnetic attraction of the magnetic portion upon impact with a target and deploy from the retracted position to the deployed position upon impact with a target. 
 
     
     
       2. The broadhead arrowhead of  claim 1 , wherein each cutting blade includes a deployable end that extends outwardly when the broadhead impacts a target, and wherein the magnetic portion is adjacent the deployable ends of the cutting blades when the cutting blades are in the retracted position. 
     
     
       3. The broadhead arrowhead of  claim 2 , wherein the length of the magnetic portion along an axis substantially parallel to the arrow shaft is substantially less than the length of the cutting blades along the axis substantially parallel to the arrow shaft when the cutting blades are in the retracted position. 
     
     
       4. The broadhead arrowhead of  claim 1 , wherein each cutting blade includes a pivoting end around which the cutting blade rotates when the broadhead arrowhead impacts a target, and wherein the magnetic portion is adjacent the pivoting ends of the cutting blades. 
     
     
       5. The broadhead arrowhead of  claim 4 , wherein the length of the magnetic portion along an axis substantially parallel to the arrow shaft is substantially less than the length of the cutting blades along the axis substantially parallel to the arrow shaft when the cutting blades are in the retracted position. 
     
     
       6. The broadhead arrowhead of  claim 1 , wherein the broadhead body is cylindrical and the magnetic portion forms a ring magnet adjacent the rear portion of the cylinder. 
     
     
       7. The broadhead arrowhead of  claim 1 , wherein the broadhead body is cylindrical and the magnetic portion forms a ring magnet adjacent the forward portion of the cylinder. 
     
     
       8. The broadhead arrowhead of  claim 1 , wherein the inner surfaces of the cutting blades include larger diameter portions adapted to receive the magnetic portion of the broadhead body when the cutting blades are in the retracted position. 
     
     
       9. The broadhead arrowhead of  claim 1 , wherein the cutting blades are elongated, each cutting blade having a pivoting end pivotally attached to the shaft and a deployable end, and wherein the magnetic portion is localized near the deployable ends of the cutting blades when the cutting blades are in the retracted position. 
     
     
       10. The broadhead arrowhead of  claim 1 , comprising:
 a pointed tip connected to the broadhead body and adapted to penetrate a target, wherein the cutting blades extend from the pivot location rearward from the pointed tip while the cutting blades are in the retracted position. 
 
     
     
       11. The arrowhead of  claim 1 , wherein the cutting blades have deployable ends arranged rearward of the pivoting ends while the blades are in the retracted position. 
     
     
       12. A method, comprising:
 magnetically holding cutting blades of a broadhead arrowhead in a retracted position during launch and flight of the arrowhead; 
 overcoming the magnetic attraction holding the blades in the retracted position when the arrowhead impacts a target; and 
 deploying the blades outwardly from the retracted position to a deployed position when the arrowhead impacts the target by rotating deployable ends of the cutting blades around pivoting ends of the cutting blades, the pivoting ends being pivotally attached to the broadhead arrowhead; and wherein the deployable ends of the cutting blades are rearward of the pivoting ends while the blades are in a retracted position. 
 
     
     
       13. The method of  claim 12 , comprising:
 applying a force to the blades that overcomes the magnetic attraction holding the blades in the retracted position when the arrowhead impacts the target. 
 
     
     
       14. The method of  claim 12 , comprising:
 positioning a magnetic portion adjacent the deployable ends of the cutting blades, the magnetic portion having a length along the flight direction that is substantially less than the length of the cutting blades along the flight direction while the blades are in the retracted position. 
 
     
     
       15. The method of  claim 12 , wherein the magnetic attraction holding the blades in a retracted position is provided by a ring magnet abutting the cutting blades. 
     
     
       16. A broadhead arrowhead assembly, comprising:
 elongated cutting blades; 
 a central body connected to the elongated cutting blades, wherein each elongated cutting blade includes a deployable end adapted to extend outwardly from the central body when the arrowhead impacts a target; and 
 a magnetic portion of said central body is localized near the deployable ends of the elongated cutting blades when the elongated cutting blades are in the retracted position; 
 wherein the elongated cutting blades and the magnetic portion are adapted to attach to an arrow shaft; 
 wherein the magnetic portion magnetically holds the elongated cutting blades in a retracted position during launch and flight, the elongated cutting blades being oriented substantially parallel to the arrow shaft to which the arrowhead is attached when in the retracted position; and 
 wherein impact of the broadhead arrowhead on a target activates a mechanism that opens the blades from the retracted position to a deployed position with the blades extending outwardly in a substantially nonparallel direction to the arrow shaft. 
 
     
     
       17. The broadhead arrowhead assembly of  claim 16 , wherein the magnetic portion is part of a central body connected to the elongated cutting blades and the elongated cutting blades are adapted to extend outwardly from the central body when the arrowhead impacts a target. 
     
     
       18. The broadhead arrowhead assembly of  claim 16 , wherein the magnetic portion extends along a substantial portion of the length of the elongated cutting blades when the elongated cutting blades are in the retracted position. 
     
     
       19. The assembly of  claim 16 , wherein the magnetic portion forms a ring magnet abutting the cutting blades. 
     
     
       20. The assembly of  claim 16 , wherein the deployable ends of the cutting blades are rearward of the pivoting ends while the blades are in a retracted position.